Supplemental Equity and Comprehensive Income Information - AOCI rf (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	$ 9,796
Other comprehensive income (loss), before tax:
Stockholders' Equity Attributable to 3M, Ending Balance	9,703
ASU 2016-02 Leases
AOCI Attributable to 3M, Net of Tax Roll Forward
Impact of ASUs	14
Other comprehensive income (loss), before tax:
Impact of ASUs	14
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(6,866)	$ (7,026)
Other comprehensive income (loss), before tax:
Amounts before reclassifications	116	47
Amounts reclassified out	97	185
Total other comprehensive income (loss), before tax	213	232
Tax effect	(46)	(9)
Total other comprehensive income (loss), net of tax	167	223
Stockholders' Equity Attributable to 3M, Ending Balance	(7,552)	(6,803)
Accumulated Other Comprehensive Income (Loss) | ASU 2018-02 Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income
AOCI Attributable to 3M, Net of Tax Roll Forward
Impact of ASUs	(853)
Other comprehensive income (loss), before tax:
Impact of ASUs	(853)
Accumulated Other Comprehensive Income (Loss) | ASU 2016-02 Leases
AOCI Attributable to 3M, Net of Tax Roll Forward
Impact of ASUs	(853)
Other comprehensive income (loss), before tax:
Impact of ASUs	(853)
Cumulative Translation Adjustment
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(2,098)	(1,638)
Other comprehensive income (loss), before tax:
Amounts before reclassifications	103	129
Total other comprehensive income (loss), before tax	103	129
Tax effect	(26)	39
Total other comprehensive income (loss), net of tax	77	168
Stockholders' Equity Attributable to 3M, Ending Balance	(2,034)	(1,470)
Cumulative Translation Adjustment | ASU 2016-02 Leases
AOCI Attributable to 3M, Net of Tax Roll Forward
Impact of ASUs	(13)
Other comprehensive income (loss), before tax:
Impact of ASUs	(13)
Gains (losses) associated with defined benefit pension and postretirement plans amortization
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	(4,832)	(5,276)
Other comprehensive income (loss), before tax:
Amounts reclassified out	104	151
Total other comprehensive income (loss), before tax	104	151
Tax effect	(20)	(35)
Total other comprehensive income (loss), net of tax	84	116
Stockholders' Equity Attributable to 3M, Ending Balance	(5,565)	(5,160)
Gains (losses) associated with defined benefit pension and postretirement plans amortization | ASU 2016-02 Leases
AOCI Attributable to 3M, Net of Tax Roll Forward
Impact of ASUs	(817)
Other comprehensive income (loss), before tax:
Impact of ASUs	(817)
Cash flow hedging instruments gains (losses)
AOCI Attributable to 3M, Net of Tax Roll Forward
Stockholders' Equity Attributable to 3M, Beginning Balance	64	(112)
Other comprehensive income (loss), before tax:
Amounts before reclassifications	13	(82)
Amounts reclassified out	(7)	34
Total other comprehensive income (loss), before tax	6	(48)
Tax effect		(13)
Total other comprehensive income (loss), net of tax	6	(61)
Stockholders' Equity Attributable to 3M, Ending Balance	47	$ (173)
Cash flow hedging instruments gains (losses) | ASU 2016-02 Leases
AOCI Attributable to 3M, Net of Tax Roll Forward
Impact of ASUs	(23)
Other comprehensive income (loss), before tax:
Impact of ASUs	$ (23)